Directional Grain Growth of Tungsten Particles by In Situ Laser Sintering for Precise Conductive Patterns in Heating Applications

We introduce an integrated patterning technique combining ultraviolet (UV) laser sintering and precision ink dispensing to fabricate conductive tungsten patterns exhibiting distinctive directional rod-like grain growth. By systematically optimizing dispensing and laser parameters, we achieved consistent pattern geometries and significantly enhanced electrical properties. Higher laser energy densities specifically induced pronounced directional rod-like grain structures within tungsten particles, markedly improving electrical conductivity up to 2.61 × 105 S/m. Steady-state heat transfer analysis validated that the laser provided adequate localized heating essential for effective particle sintering. The in situ process allows localized sintering of dispensed tungsten patterns, enabling fabrication of precise conductive patterns with controlled microstructures. A heater prototype fabricated by this method exhibited stable and uniform heating performance, confirming its practical applicability. These results establish UV laser sintering integrated with ink dispensing as a powerful, scalable approach for fabricating conductive patterns with controlled directional grain growth, ideal for advanced electronic and thermal management applications.